The present invention relates to the general art of electrical transmission or interconnection systems, and to the particular field of substitute or emergency power supplies.
In many instances, it is desirable to provide an emergency power system which will automatically supply continuous auxiliary electric power when a main source of power, such as a utility, falls below a certain level. This situation may be caused by a power loss at the utility, a break in a supply line or the like. There are many examples of situations that require a continuous supply of power, even when a main source of power is down. Hospitals, telecommunications centers, industrial plants, as well as any computer user all require a continuous source of power. Interruptions in power can damage delicate electronic instruments as well as wipe out computer memories. The loss of all or a portion of a main power supply occurs in the United States, and can be common in developing countries.
Therefore, the art has several examples of auxiliary power sources. However, it is not sufficient to merely supply power to a load during main power supply downtime, such power should be supplied in a manner that is most efficient and does not damage equipment during a changeover from the main power source to the auxiliary power source. Many delicate electronic instruments are sensitive to spikes, or other less severe variations, in power, even if the spikes are quite small. This is especially true if the equipment is subject to a number of such spikes which might occur if the main power source is subject to variations in output.
Therefore, there is a need for an auxiliary power source that can take over supplying power to a load when a main source of power goes away or falls below a specified limit and does so in a manner that is smooth and does not create a spike during a changeover from the main supply to the auxiliary supply.
In the case of large loads, the art has suggested using generators that are driven by engines to supply the auxiliary power to the load. The engines are often thermal power engines, such as internal combustion engines, diesel engines or the like. However, even a well-primed and pre-heated thermal engine can require as much as two to three seconds to come up to operating speed and cannot assume full load until such time as it is operating at its operating speed. Thus, there is a delay in switching over to such engine-driven auxiliary power supplies that is associated with an inherent condition of the engine that cannot be changed in any significant manner.
However, two to three seconds is an eternity when electronic equipment is concerned. During that delay time, electronic memories can be totally lost, equipment shut off in a manner that damages that equipment or equipment associated therewith, and significant spikes developed, among many other undesirable results.
Therefore, there is a need for an auxiliary power system that can provide power to a load as quickly as necessary to maintain electronic components in an operating condition even during the switch over from main power to auxiliary power.
The art also contains examples of auxiliary power systems that utilize flywheels in connection with the auxiliary power system. These systems convert the kinetic energy of a rotating mass into electrical power during the change over from the main power source to the power supplied by an auxiliary engine driving a generator connected to the lines used to transfer power to a load, or loads. Most flywheel systems are not sufficient to supply power to large loads such as might be found in large businesses or the like, even for the short time associated with a change over to an auxiliary power system.
Therefore, there is a need for an auxiliary power system that can accommodate large loads during a change over from a main power system to an auxiliary power system and can provide a smooth transition.
Still further, since the energy associated with a rotating flywheel is directly proportional to the mass as well as directly proportional to the square of the velocity of rotation, more energy can be realized from such a rotating flywheel by increasing its size and/or increasing its speed of rotation. Increasing the size of a flywheel is not as efficient as increasing the speed of rotation due to the relationship between mass and energy and between velocity and energy. However, even beyond that, increasing the size of a flywheel may not be efficient from the standpoint of the structures associated with the flywheel. These structures must be large enough to accommodate the flywheel and if large amounts of energy are required from the flywheel, the structures associated with the flywheel may become unwieldy.
However, some flywheel speeds in flywheels associated with prior art systems are limited by the speed of rotation of the equipment associated with the flywheel.
Therefore, there is a need for a standby power generating system that makes efficient use of a flywheel.
The inventor of the present invention has observed that a flywheel rotating in a horizontal plane can be safely operated at a rotational speed greater than a flywheel mounted to rotate in a vertical plane. However, most engines and motor/generator units suitable for use in an auxiliary power system have shafts that are mounted to rotate in a vertical plane. Accordingly, it may be difficult and complicated to adapt a flywheel rotating in a horizontal plane to couple to a shaft that is rotating in a vertical plane. Yet, such horizontally rotating flywheel is most useful in auxiliary power systems associated with large loads.
While the art does contain some examples of auxiliary power systems having large flywheels, such systems have many parts, are complex, expensive, not fully reliable and often take up a large amount of space, while not being as efficient as possible.
Therefore, there is a need for an auxiliary power system that can accommodate large loads during a change over from a main power system to an auxiliary power system and can provide a smooth transition and is simple, reliable, inexpensive and makes efficient use of space.
Still further, many engines used in existing auxiliary power supply systems are designed to operate at 2200 rpm for maximum horsepower, torque and fuel efficiency. However, many motor/generators used in such systems are designed to operate at 1500 to 1800 rpm to generate power in the 50 Hz to 60 Hz range required for most industrial loads. Accordingly, the engines used in existing auxiliary power systems must be de-rated in horsepower and thus lose efficiency.
Therefore, there is a need for an auxiliary power system that can use existing engines without de-rating those engines whereby engine efficiency is not compromised by use in such auxiliary power systems.
Overall, there is a need for a cost-effective, reliable engine integrated system that can utilize a high capacity flywheel and extract all useable energy from the flywheel while maintaining a generator output constant for a wide range of conditions.
It is a main object of the present invention to provide an auxiliary power source that can take over supplying power to a load when a main source of power goes away or falls below a specified limit and does so in a manner that does not adversely affect the load.
It is another object of the present invention to provide an auxiliary power source that can take over supplying power to a load when a main source of power goes away or falls below a specified limit and does so in a manner that is smooth and does not create a spike during a changeover from the main supply to the auxiliary supply.
It is another object of the present invention to provide an auxiliary power system that can provide power to a load as quickly as necessary to maintain electronic components in an operating condition even during the switch over from main power to auxiliary power.
It is another object of the present invention to provide an auxiliary power system that can accommodate large loads during a change over from a main power system to an auxiliary power system and can provide a smooth transition.
It is another object of the present invention to provide an auxiliary power system that can accommodate large loads during a change over from a main power system to an auxiliary power system and can provide a smooth transition and is simple, reliable, inexpensive and makes efficient use of space.
It is another object of the present invention to provide an auxiliary power system that can use existing engines without de-rating those engines whereby engine efficiency is not compromised by use in such auxiliary power systems.
It is another object of the present invention to provide an auxiliary power system that can accommodate large loads during a change over from a main power system to an auxiliary power system and makes efficient use of a flywheel.
It is another object of the present invention to provide an auxiliary power system that can use existing engines and makes efficient use of a flywheel.
It is another object of the present invention to provide a cost-effective, reliable engine integrated system that can utilize a high capacity flywheel and extract all useable energy from the flywheel while maintaining a generator output constant for a wide range of conditions.
It is another object of the present invention to provide a no-break emergency power system for large critical loads.
These, and other, objects are achieved by an auxiliary power supply system that can safely accommodate a large flywheel and can couple an engine operating at its rated capacity to a motor/generator unit that is sized to provide power at a desired level and frequency, even if that level and frequency are associated with a motor/generator operation at a capacity different from the rated capacity of the engine. Such a system will be able to smoothly and efficiently transfer power from a main source to the auxiliary source even if large amounts of power are required.
Specifically, the auxiliary power system embodying the present invention includes a large flywheel that is mounted to rotate in a horizontal plane, and a coupling unit that can efficiently couple an engine output shaft that is rotating in a vertical plane to an input/output shaft of a motor/generator that is also rotating in a vertical plane and to the horizontally rotating flywheel.
The coupling unit also permits matching the output of the engine to the desired input of the motor/generator while allowing the engine to operate at its most efficient level. The system of the present invention also permits a flywheel to operate at any selected rotational speed, even if that speed differs from the output rotational speed of either the engine or the motor/generator. Still further, the auxiliary power unit of the present invention is amenable to being ganged together with other auxiliary power units to provide large amounts of power when necessary.